A device of the above kind is described in the specification of U.S. Pat. No. 4,613,029 and that of the corresponding French published patent application No. FR 2 496 210A. In those documents, the device includes third resilient means which are interposed between the damper plate and the hub, and which are adapted to enable the set of teeth of the damper plate to come into circumferential engagement with those of the hub, with this engagement being accompanied by a braking effect such as to reduce the impact or noise associated therewith. Thus the two sets of teeth come only gently into engagement with each other, and noise is avoided.
In one embodiment, the third resilient means comprise at least one ring which is engaged around one of the teeth of one of the sets of teeth, in a groove in the tooth concerned. This ring is arranged to be compressed by the cooperating teeth of the other set. In other embodiments, resilient blocks are incorporated in recesses formed in the sets of teeth.
Such arrangements are effective when the device is new, but are susceptible to deterioration over the course of time. In addition, the sets of teeth are weakened, and the torque which can be transmitted is therefore not as high as is sometimes desirable.